The present invention relates to computer-implemented methods and system for analysing a biomarker which cycles in a subject. In some other aspects, the present invention relates to analysing a biomarker which at least initially increases or decreases in amount in a subject following a treatment for a disease. In further aspects, the present invention relates to computer-implemented methods and systems for determining a preferred time to administer a therapy to treat a disease in a subject. The present invention also relates to computer program product to implement the methods. Further, the present invention relates to methods of determining the timing of treating a disease in a subject in which the immune system is cycling.